Rubella in Austria 2008-2009: no longer a typical childhood disease.

BACKGROUND: In February 2009, a cluster of rubella cases was recognized in Austria occurring between calendar weeks 3 and 7, 2009 after a long period of low rubella virus activity. A nationwide 2-dose measles, mumps, and rubella vaccination program had been introduced in 1994 to prevent this childhood illness. METHODS: An epidemiologic investigation was conducted to describe the cluster by time, place, and person. A confirmed outbreak case was defined as a febrile person (1) with generalized rash, which was laboratory confirmed or epidemiologically linked to a laboratory confirmed case and (2) who became ill after October 1, 2008 in the 2 affected provinces. A probable outbreak case was defined as any person meeting the clinical criteria of rubella and meeting the criterion 2 of a confirmed outbreak case. All cases were telephone interviewed on demographics and vaccination status. RESULTS: A total of 355 outbreak cases (including 247 confirmed cases) occurred in 2 neighboring Austrian provinces from mid-October 2008 until the end of June 2009, peaking in mid-March. The 2 most-affected age groups were 15 to 19 (44.4%) and 20 to 24 year olds (32.4%). The vaccination status was available for 230 cases; 10% of cases had received 1 measles, mumps, and rubella vaccine dose. No case had received 2 doses. Of the 146 female cases, one laboratory-confirmed rubella infection in a pregnant 18-year-old native Austrian resulted in elective abortion. CONCLUSIONS: These findings underline the waning epidemiologic role of children in maintaining the circulation of rubella virus and indicate that additional vaccination activities targeting >15 year olds are needed to achieve the 2010 WHO target for rubella elimination in the European Region.

Dynamics of antigenic and genetic changes in the hemagglutinins of influenza A/H3N2 viruses of three consecutive seasons (2002/2003 to 2004/2005) in Austria.

Human influenza viruses are subject to continuous antigenic drift and this phenomenon poses great problems for the annual production of vaccines which should ideally be manufactured from strains closely matching the predominant strains of the coming influenza season. We have investigated the dynamics of antigenic and genetic changes in the hemagglutinins of circulating influenza A/H3N2 strains in three consecutive seasons (2002/2003 to 2004/2005) in Austria by sequence analysis of the HA1 domain and by antigenic characterization using a hemagglutination inhibition assay. Each of the three seasons was dominated by a single and different H3N2 variant, but in all cases sequencing revealed the co-circulation of a drift variant which would have been missed by conventional antigenic analysis. These emerging strains always showed already a close genetic relationship to the dominating strain of the following season. Our results underscore the value of monitoring seasonal influenza strain dynamics by sequence analysis as an instrument that can provide important and timely information on the appearance of strains with epidemiologic significance.